Two 4 megaton bombs, model Mark 39, broke off from the bomber as it went into a tailspin and crashed. One bomb landed safely, with all four safety mechanisms intact. The other bomb however, experience three separate failures of its safety mechanisms, with only a single low-voltage switch saving the East Coast from disaster. The bomb landed twelve miles outside of Goldsboro, North Carolina. For years the government had denied that single switch saved the lives of millions.

A 1969 government document outlines exactly how close the U.S. was to the third nuclear explosion in a populated area. The document, which was obtained by a Freedom of Information Act request, concludes that "one simple, dynamo-technology, low voltage switch stood between the United States and a major catastrophe." The explosion would have spread fatal amounts of fallout all the way up to New York City.

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Apparently, when the bomb hit the ground, the firing mechanism was activated, however, that final safety mechanism held, saving millions of lives. Still, the report details just how unsafe the transport of nuclear weapons was (and remains to be). Schlosser has just released a book detailing the at least 700 "significant" accidents that involved thousands of nuclear weapons between 1950 and 1968.

"The US government has consistently tried to withhold information from the American people in order to prevent questions being asked about our nuclear weapons policy," Schlosser told the Guardian. "We were told there was no possibility of these weapons accidentally detonating, yet here's one that very nearly did."

Only three days after Kennedy's inaugural address, the U.S. was just one switch away from calamity.